The document serves as an educational guide on electrocardiography (ECG), describing its significance in diagnosing cardiac conditions and detailing the anatomy of the cardiac conduction system. It outlines the placement of electrodes, types of ECG leads, and the importance of prehospital ECGs in improving patient outcomes. The lecture aims to equip participants with the knowledge to interpret ECG waveforms and recognize various heart issues.

1. Basics of Electrocardiography (ECG)
Birhanu Chekol (BSc. MSc.)
Senior Anesthetist and Paramedic specialist
3/13/2023
1

2.  Objectives
 Introduction
 Cardiac conduction System
 Placement of electrodes
 ECG lead
 Summary
 References
2
Outline

3. Upon completion of this lecture, you will be able to:-
 Define ECG
 Describe the cardiac conduction system
 Identify the waves of the ECG
 Explain the different types of ECG leads
 Describe the importance of prehospital ECG
3
Objectives

4. Sinoatrial node
AV node
Bundle of His
Bundle Branches
Purkinje fibers
4
Introduction

5.  The electrocardiogram (EKG) is a representation of the
electrical events of the cardiac cycle.
 ECG is the gold standard for the noninvasive diagnosis of
cardiac diseases and may occasionally be the only marker
for the presence of heart disease
 Each event has a distinctive waveform
5
Introduction

6.  A typical ECG tracing is a repeating cycle of three electrical
entities:
a. P wave
b. QRS complex
c. T wave
6
Introduction

7. With ECG we can identify…
 Arrhythmias
 Myocardial ischemia and infarction
 Pericarditis
 Chamber hypertrophy
 Electrolyte disturbances (i.e. hyperkalemia, hypokalemia)
7
Introduction

8.  Ten electrodes are used for a 12-lead ECG.
 Color-coded
8
Placement of ECG electrodes

9. Chest (Precordial) Lead Placement
 V1: 4th intercostal space, right sternal border
 V2: 4th intercostal space, left sternal border
 V3: Midway between leads V2 and V4
 V4: 5th intercostal space, midclavicular line
 V5: 5th intercostal space, anterior axillary line
 V6: 5th intercostal space, mid axillary line
9
Placement of ECG electrodes

10.  Leads (cameras) view at different angles from the heart.
10
ECG Leads
Leads actually don’t
refer to the
electrodes, but rather
the perspectives
through which we
view the heart. So a
"12-lead" means
looking at the heart
from 12 angles, which
we obtain through 10
electrodes.

11.  There are 12 conventional ECG leads
 These leads are divided in to two group;
 Six extremity (limb) leads and
 Six chest ( precordial ) leads.
 The limb leads are further subdivided into:
 Three bipolar lead (I,II,III) and
 Three unipolar leads (aVR, aVL, and aVF).
11
ECG Leads

12. 12
ECG Leads

13.  Early recognition and fast, appropriate treatment can
prevent the extension of an MI
 Early recognition = early intervention
 An important diagnostic tool will also be the patient’s
general appearance
13
Why Are We doing Pre-hospital
ECG’s?

14.  An electrocardiogram is a painless, noninvasive way to
help diagnose many common heart problems.
 The prehospital 12-lead ECG is associated with better
survival in patients with acute coronary syndrome (ACS)
 Early recognition = early intervention
14
Summary

15.  Ecgmadesimple.com
 Book: ECGs for the Emergency Physician – Amal Mattu
 lifeinthefastlane.com/ecg-library
15
References

16. 16
3/13/2023
Thank
you!!!